It is well-known that an electromechanical relay (EMR) uses a physical moving part to connect contacts within the output component of the relay. The movement of this contact is generated using electromagnetic forces from the low-power input signal, allowing the completion of the circuit that contains the high-power signal. EMR typically use solenoids, coils, magnetic fields, springs and mechanical contacts to operate and switch a supply.
A solid-state relay (SSR) uses a low power electrical signal to generate an optical semiconductor signal, typically with an opto-coupler, that transmits and energizes the output signal. When activated, the input optical signal acts as the drive path to power a “switch” that allows a high voltage and or current signal to pass through the SSR's output component. Unlike EMR, the SSR lacks moving parts, hence the device is solid-state.
To date, there are no non-electromechanical product offerings available in the searchable market literature which address the need for an adjustable, high-current, solid-state solution (e.g., relay, contactor). Current options are limited and even those that may be available are non-adjustable (non-variable control). Further, solid state relays with very high current ratings (e.g., greater than 150 A) are still very expensive to buy due to their power semiconductor and heat sinking requirements, and as such, cheaper electromechanical contactors are frequently still used.
Conventional power control methods such as pulse-width modulation (PWM), pulse-frequency modulation (PFM), or various combinations of such modulation, are typically implemented with a dedicated power control integrated circuit (IC) which can involve size, cost, and circuit complexities and the associated consequences.
Not only can the disclosed device provide for the elimination of a dedicated modulation IC and associated circuitry, it provides improvements in size, cost, performance, complexity and can be used for a vast host of applications.